The retina is more susceptible to damage caused by toxic and environmental agents than most other bodily tissues. At present, the toxicology of the retina lacks a detailed biochemical or physiological basis and is primarily empirical. In preliminary studies with experimental animals I have obtained evidence for the presence of glutathione-S-transferase activity in the retina and retinal pigment epithelium (RPE). Glutathione-S-transferase enzymes are thought to play a vital role in the detoxification of many drugs and chemicals. These enzymes may also play a role in protecting the biomembranes of retinal tissues from toxic lipid hydroperoxides. The primary goal of this pilot project is to develop effective procedures for the purification of glutathione-S-transferase enzymes from rather limited amounts of retinal tissues. In particular, we will test the feasibility of utilizing high performance liquid chromatography since this method offers very high resolution and high yields. A second goal of this project is to study the biochemical properties of the purified retinal and RPE glutathione-S-transferase enzymes. The properties that will be measured include molecular weight, subunit structure, isoelectric point, and substrate specificities. These biochemical studies will hopefully provide a framework in which more physiologically significant studies of retinal toxicology can be undertaken.